package main

import (
	"crypto/tls"
	"fmt"

	"github.com/certifi/gocertifi"
)

func checkHost(host string) {
	//load ca certs. bundle
	certPool, err := gocertifi.CACerts()
	conn, err := tls.Dial("tcp", host, &tls.Config{RootCAs: certPool})

	if err != nil {
		fmt.Println(err)
		return
	}
	defer conn.Close()

	checkedCerts := make(map[string]struct{})
	for _, chain := range conn.ConnectionState().VerifiedChains {
		for _, cert := range chain {
			if _, checked := checkedCerts[string(cert.Signature)]; checked {
				continue
			}
			checkedCerts[string(cert.Signature)] = struct{}{}
			fmt.Println(cert.Subject.CommonName)
			fmt.Println(cert.NotAfter)
		}
	}

	return
}

func main() {

	checkHost("blog.prskavec.net:443")
}